package testjava;

import java.io.DataInput;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.io.UTFDataFormatException;

public class EndianInputStream extends FilterInputStream implements DataInput {

    /**
     * Creates a DataInputStream that uses the specified underlying InputStream.
     *
     * @param in
     *            the specified input stream
     */
    public EndianInputStream(InputStream in) {
        super(in);
    }

    /**
     * working arrays initialized on demand by readUTF
     */
    private byte bytearr[] = new byte[80];
    private char chararr[] = new char[80];

    /**
     * Reads some number of bytes from the contained input stream and stores
     * them into the buffer array <code>b</code>. The number of bytes actually
     * read is returned as an integer. This method blocks until input data is
     * available, end of file is detected, or an exception is thrown.
     * 
     * <p>
     * If <code>b</code> is null, a <code>NullPointerException</code> is thrown.
     * If the length of <code>b</code> is zero, then no bytes are read and
     * <code>0</code> is returned; otherwise, there is an attempt to read at
     * least one byte. If no byte is available because the stream is at end of
     * file, the value <code>-1</code> is returned; otherwise, at least one byte
     * is read and stored into <code>b</code>.
     * 
     * <p>
     * The first byte read is stored into element <code>b[0]</code>, the next
     * one into <code>b[1]</code>, and so on. The number of bytes read is, at
     * most, equal to the length of <code>b</code>. Let <code>k</code> be the
     * number of bytes actually read; these bytes will be stored in elements
     * <code>b[0]</code> through <code>b[k-1]</code>, leaving elements
     * <code>b[k]</code> through <code>b[b.length-1]</code> unaffected.
     * 
     * <p>
     * The <code>read(b)</code> method has the same effect as: <blockquote>
     * 
     * <pre>
     * read(b, 0, b.length)
     * </pre>
     * 
     * </blockquote>
     *
     * @param b
     *            the buffer into which the data is read.
     * @return the total number of bytes read into the buffer, or
     *         <code>-1</code> if there is no more data because the end of the
     *         stream has been reached.
     * @exception IOException
     *                if the first byte cannot be read for any reason other than
     *                end of file, the stream has been closed and the underlying
     *                input stream does not support reading after close, or
     *                another I/O error occurs.
     * @see java.io.FilterInputStream#in
     * @see java.io.InputStream#read(byte[], int, int)
     */
    public final int read(byte b[]) throws IOException {
        return in.read(b, 0, b.length);
    }

    /**
     * Reads up to <code>len</code> bytes of data from the contained input
     * stream into an array of bytes. An attempt is made to read as many as
     * <code>len</code> bytes, but a smaller number may be read, possibly zero.
     * The number of bytes actually read is returned as an integer.
     *
     * <p>
     * This method blocks until input data is available, end of file is
     * detected, or an exception is thrown.
     *
     * <p>
     * If <code>len</code> is zero, then no bytes are read and <code>0</code> is
     * returned; otherwise, there is an attempt to read at least one byte. If no
     * byte is available because the stream is at end of file, the value
     * <code>-1</code> is returned; otherwise, at least one byte is read and
     * stored into <code>b</code>.
     *
     * <p>
     * The first byte read is stored into element <code>b[off]</code>, the next
     * one into <code>b[off+1]</code>, and so on. The number of bytes read is,
     * at most, equal to <code>len</code>. Let <i>k</i> be the number of bytes
     * actually read; these bytes will be stored in elements <code>b[off]</code>
     * through <code>b[off+</code><i>k</i><code>-1]</code>, leaving elements
     * <code>b[off+</code><i>k</i><code>]</code> through
     * <code>b[off+len-1]</code> unaffected.
     *
     * <p>
     * In every case, elements <code>b[0]</code> through <code>b[off]</code> and
     * elements <code>b[off+len]</code> through <code>b[b.length-1]</code> are
     * unaffected.
     *
     * @param b
     *            the buffer into which the data is read.
     * @param off
     *            the start offset in the destination array <code>b</code>
     * @param len
     *            the maximum number of bytes read.
     * @return the total number of bytes read into the buffer, or
     *         <code>-1</code> if there is no more data because the end of the
     *         stream has been reached.
     * @exception NullPointerException
     *                If <code>b</code> is <code>null</code>.
     * @exception IndexOutOfBoundsException
     *                If <code>off</code> is negative, <code>len</code> is
     *                negative, or <code>len</code> is greater than
     *                <code>b.length - off</code>
     * @exception IOException
     *                if the first byte cannot be read for any reason other than
     *                end of file, the stream has been closed and the underlying
     *                input stream does not support reading after close, or
     *                another I/O error occurs.
     * @see java.io.FilterInputStream#in
     * @see java.io.InputStream#read(byte[], int, int)
     */
    public final int read(byte b[], int off, int len) throws IOException {
        return in.read(b, off, len);
    }

    /**
     * See the general contract of the <code>readFully</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @param b
     *            the buffer into which the data is read.
     * @exception EOFException
     *                if this input stream reaches the end before reading all
     *                the bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final void readFully(byte b[]) throws IOException {
        readFully(b, 0, b.length);
    }

    /**
     * See the general contract of the <code>readFully</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @param b
     *            the buffer into which the data is read.
     * @param off
     *            the start offset of the data.
     * @param len
     *            the number of bytes to read.
     * @exception EOFException
     *                if this input stream reaches the end before reading all
     *                the bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final void readFully(byte b[], int off, int len) throws IOException {
        if (len < 0) throw new IndexOutOfBoundsException();
        int n = 0;
        while (n < len) {
            int count = in.read(b, off + n, len - n);
            if (count < 0) throw new EOFException();
            n += count;
        }
    }

    /**
     * See the general contract of the <code>skipBytes</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @param n
     *            the number of bytes to be skipped.
     * @return the actual number of bytes skipped.
     * @exception IOException
     *                if the contained input stream does not support seek, or
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     */
    public final int skipBytes(int n) throws IOException {
        int total = 0;
        int cur = 0;

        while ((total < n) && ((cur = (int) in.skip(n - total)) > 0)) {
            total += cur;
        }

        return total;
    }

    /**
     * See the general contract of the <code>readBoolean</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the <code>boolean</code> value read.
     * @exception EOFException
     *                if this input stream has reached the end.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final boolean readBoolean() throws IOException {
        int ch = in.read();
        if (ch < 0) throw new EOFException();
        return (ch != 0);
    }

    /**
     * See the general contract of the <code>readByte</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next byte of this input stream as a signed 8-bit
     *         <code>byte</code>.
     * @exception EOFException
     *                if this input stream has reached the end.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final byte readByte() throws IOException {
        int ch = in.read();
        if (ch < 0) throw new EOFException();
        return (byte) (ch);
    }

    /**
     * See the general contract of the <code>readUnsignedByte</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next byte of this input stream, interpreted as an unsigned
     *         8-bit number.
     * @exception EOFException
     *                if this input stream has reached the end.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final int readUnsignedByte() throws IOException {
        int ch = in.read();
        if (ch < 0) throw new EOFException();
        return ch;
    }

    /**
     * See the general contract of the <code>readShort</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next two bytes of this input stream, interpreted as a signed
     *         16-bit number.
     * @exception EOFException
     *                if this input stream reaches the end before reading two
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final short readShort() throws IOException {
        int ch1 = in.read();
        int ch2 = in.read();
        if ((ch1 | ch2) < 0) throw new EOFException();
        return (short) ((ch2 << 8) + (ch1 << 0));
    }

    /**
     * See the general contract of the <code>readUnsignedShort</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next two bytes of this input stream, interpreted as an
     *         unsigned 16-bit integer.
     * @exception EOFException
     *                if this input stream reaches the end before reading two
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final int readUnsignedShort() throws IOException {
        int ch1 = in.read();
        int ch2 = in.read();
        if ((ch1 | ch2) < 0) throw new EOFException();
        return (ch2 << 8) + (ch1 << 0);
    }

    /**
     * See the general contract of the <code>readChar</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next two bytes of this input stream, interpreted as a
     *         <code>char</code>.
     * @exception EOFException
     *                if this input stream reaches the end before reading two
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final char readChar() throws IOException {
        int ch1 = in.read();
        int ch2 = in.read();
        if ((ch1 | ch2) < 0) throw new EOFException();
        return (char) ((ch2 << 8) + (ch1 << 0));
    }

    /**
     * See the general contract of the <code>readInt</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next four bytes of this input stream, interpreted as an
     *         <code>int</code>.
     * @exception EOFException
     *                if this input stream reaches the end before reading four
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final int readInt() throws IOException {
        int ch1 = in.read();
        int ch2 = in.read();
        int ch3 = in.read();
        int ch4 = in.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0) throw new EOFException();
        return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0));
    }

    private byte readBuffer[] = new byte[8];

    /**
     * See the general contract of the <code>readLong</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next eight bytes of this input stream, interpreted as a
     *         <code>long</code>.
     * @exception EOFException
     *                if this input stream reaches the end before reading eight
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.FilterInputStream#in
     */
    public final long readLong() throws IOException {
        readFully(readBuffer, 0, 8);
        return (((long) readBuffer[7] << 56) + ((long) (readBuffer[6] & 255) << 48) + ((long) (readBuffer[5] & 255) << 40)
                + ((long) (readBuffer[4] & 255) << 32) + ((long) (readBuffer[3] & 255) << 24) + ((readBuffer[2] & 255) << 16)
                + ((readBuffer[1] & 255) << 8) + ((readBuffer[0] & 255) << 0));
    }

    /**
     * See the general contract of the <code>readFloat</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next four bytes of this input stream, interpreted as a
     *         <code>float</code>.
     * @exception EOFException
     *                if this input stream reaches the end before reading four
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.DataInputStream#readInt()
     * @see java.lang.Float#intBitsToFloat(int)
     */
    public final float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }

    /**
     * See the general contract of the <code>readDouble</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return the next eight bytes of this input stream, interpreted as a
     *         <code>double</code>.
     * @exception EOFException
     *                if this input stream reaches the end before reading eight
     *                bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @see java.io.DataInputStream#readLong()
     * @see java.lang.Double#longBitsToDouble(long)
     */
    public final double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }

    private char lineBuffer[];

    /**
     * See the general contract of the <code>readLine</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @deprecated This method does not properly convert bytes to characters. As
     *             of JDK&nbsp;1.1, the preferred way to read lines of text is
     *             via the <code>BufferedReader.readLine()</code> method.
     *             Programs that use the <code>DataInputStream</code> class to
     *             read lines can be converted to use the
     *             <code>BufferedReader</code> class by replacing code of the
     *             form: <blockquote>
     * 
     *             <pre>
     * DataInputStream d = new DataInputStream(in);
     * </pre>
     * 
     *             </blockquote> with: <blockquote>
     * 
     *             <pre>
     * BufferedReader d = new BufferedReader(new InputStreamReader(in));
     * </pre>
     * 
     *             </blockquote>
     *
     * @return the next line of text from this input stream.
     * @exception IOException
     *                if an I/O error occurs.
     * @see java.io.BufferedReader#readLine()
     * @see java.io.FilterInputStream#in
     */
    @Deprecated
    public final String readLine() throws IOException {
        char buf[] = lineBuffer;

        if (buf == null) {
            buf = lineBuffer = new char[128];
        }

        int room = buf.length;
        int offset = 0;
        int c;

        loop: while (true) {
            switch (c = in.read()) {
            case -1:
            case '\n':
                break loop;

            case '\r':
                int c2 = in.read();
                if ((c2 != '\n') && (c2 != -1)) {
                    if (!(in instanceof PushbackInputStream)) {
                        this.in = new PushbackInputStream(in);
                    }
                    ((PushbackInputStream) in).unread(c2);
                }
                break loop;

            default:
                if (--room < 0) {
                    buf = new char[offset + 128];
                    room = buf.length - offset - 1;
                    System.arraycopy(lineBuffer, 0, buf, 0, offset);
                    lineBuffer = buf;
                }
                buf[offset++] = (char) c;
                break;
            }
        }
        if ((c == -1) && (offset == 0)) {
            return null;
        }
        return String.copyValueOf(buf, 0, offset);
    }

    /**
     * See the general contract of the <code>readUTF</code> method of
     * <code>DataInput</code>.
     * <p>
     * Bytes for this operation are read from the contained input stream.
     *
     * @return a Unicode string.
     * @exception EOFException
     *                if this input stream reaches the end before reading all
     *                the bytes.
     * @exception IOException
     *                the stream has been closed and the contained input stream
     *                does not support reading after close, or another I/O error
     *                occurs.
     * @exception UTFDataFormatException
     *                if the bytes do not represent a valid modified UTF-8
     *                encoding of a string.
     * @see java.io.DataInputStream#readUTF(java.io.DataInput)
     */
    public final String readUTF() throws IOException {
        return DataInputStream.readUTF(this);
    }

}
